1. Field of the Invention
The present invention pertains to the conduction of electric current by a P-N junction rectifier, and, more particularly, to a circuit for commutating such rectifiers to the non-conducting state while simultaneously preventing the creation of relatively high current transients or "spikes".
2. Description of Related Art
In rectifiers employing P-N junction devices, in the conduction of electric current charge is temporarily stored in the rectifying junction that has to be removed when commutating the rectifier to its non-conducting state. At the time of conduction, the rectifier is essentially a short-circuit which can in many switch mode uses produce a relatively high current "spike" which undesirably increases circuit losses, electromagnetic interference as well as heating of circuit components. Prior art apparatus for reducing such current transients have relied upon storing the energy in an inductor and subsequently dumping it into a resistor for spike dissipation which disadvantageously results in substantial energy being lost and the dissipated energy results in undesirable heating of the resistor, the diode and surrounding components which can reduce reliability and require additional heat sinking. Also, the resistor value if either too large or too small will not dissipate the energy in the shortest possible time and there are tradeoffs in the selection of the resistor value which it is desirable to avoid since they can be reflected in other circuit requirements.